mattrpav opened a new pull request, #2714:
URL: https://github.com/apache/activemq/pull/2714
…queue size metric (#2584)
* Add tests confirming queueSize accounting for duplicate messages
Two end-to-end tests exercise the duplicate paths through the real broker
and confirm the messages-counter invariant (messages == 0 after drain, enqueues
- dequeues == messages).
DuplicateSendStoreRaceQueueSizeTest reproduces the async/sync duplicate send
race: an original persistent send from a useAsyncSend producer is counted and
cursor-cached while its KahaDB index update is parked on the store executor; a
duplicate resend on a different connection takes the sync store path, finds no
index row, is assigned a real sequence, passes the -1 duplicate gate, and is
counted again. After drain: messages=1, enqueues=2, dequeues=1, failing until
the store treats a sync add racing a pending async add of the same MessageId as
a duplicate.
DuplicateFromStoreEndToEndTest covers both duplicate classes without
invoking duplicateFromStore directly. The duplicate SEND is trapped by the
cursor cache audit and fully suppressed. The store RE-READ ("cursor got
duplicate from store") is a single-counted message read twice whose inflight
copy is still consumed and acked; duplicateFromStore must not decrement the
messages counter as well, or the count goes negative. A blanket decrement in
duplicateFromStore was prototyped and rejected because this test showed
messages=-2 for 4 sent and 4 consumed.
* Reject sync duplicate add racing a pending async add of the same message
With concurrentStoreAndDispatchQueues=true an async add is counted and
dispatched from the cursor cache immediately while its journal/index update
runs on the store executor. A duplicate send of the same MessageId taking the
synchronous addMessage path in that window (failover replay from an async-send
producer, arriving on a different connection so the producer audit cannot
suppress it) found no row in messageIdIndex, was assigned a real sequence, and
evaded the -1 duplicate suppression in Queue.doPendingCursorAdditions,
inflating enqueues and the queue messages counter by one for a message that is
stored and delivered once. The original's deferred index update then lost the
race and was rejected, leaving the count permanently inflated.
addMessage now consults asyncTaskMap for a pending async add of the same
MessageId before journaling. Sync callers are identified by a null
FutureOrSequenceLong (the async task's own store call carries its future),
matching the discrimination already used by the IndexAware callback. On a hit
the message is marked with the -1 duplicate sequence and skipped entirely: no
journal write, no pendingAdds entry, and the existing cursor suppression keeps
it uncounted.
(cherry picked from commit e4fd919b335299716e00d1b6ff096bb0d50deb17)
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